﻿// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.ComponentModel;
using System.ComponentModel.Design.Serialization;
using System.Drawing;
using System.Drawing.Imaging;

namespace System.Windows.Forms;

/// <summary>
///  The ImageList is an object that stores a collection of Images, most
///  commonly used by other controls, such as the ListView, TreeView, or
///  Toolbar. You can add either bitmaps or Icons to the ImageList, and the
///  other controls will be able to use the Images as they desire.
/// </summary>
[Designer($"System.Windows.Forms.Design.ImageListDesigner, {Assemblies.SystemDesign}")]
[ToolboxItemFilter("System.Windows.Forms")]
[DefaultProperty(nameof(Images))]
[TypeConverter(typeof(ImageListConverter))]
[DesignerSerializer($"System.Windows.Forms.Design.ImageListCodeDomSerializer, {Assemblies.SystemDesign}",
    $"System.ComponentModel.Design.Serialization.CodeDomSerializer, {Assemblies.SystemDesign}")]
[SRDescription(nameof(SR.DescriptionImageList))]
public sealed partial class ImageList : Component, IHandle<HIMAGELIST>
{
    private static readonly Color s_fakeTransparencyColor = Color.FromArgb(0x0d, 0x0b, 0x0c);
    private static readonly Size s_defaultImageSize = new(16, 16);

    private static int s_maxImageWidth;
    private static int s_maxImageHeight;
    private static bool s_isScalingInitialized;

    private NativeImageList? _nativeImageList;

    private ColorDepth _colorDepth = ColorDepth.Depth32Bit;
    private Size _imageSize = s_defaultImageSize;

    private ImageCollection? _imageCollection;

    // The usual handle virtualization problem, with a new twist: image
    // lists are lossy. At runtime, we delay handle creation as long as possible, and store
    // away the original images until handle creation (and hope no one disposes of the images!).
    // At design time, we keep the originals around indefinitely.
    // This variable will become null when the original images are lost.
    private List<Original>? _originals = [];
    private EventHandler? _recreateHandler;
    private EventHandler? _changeHandler;

    /// <summary>
    ///  Creates a new ImageList Control with a default image size of 16x16 pixels
    /// </summary>
    public ImageList()
    {
        if (!s_isScalingInitialized)
        {
            const int MaxDimension = 256;
            s_maxImageWidth = ScaleHelper.ScaleToInitialSystemDpi(MaxDimension);
            s_maxImageHeight = ScaleHelper.ScaleToInitialSystemDpi(MaxDimension);
            s_isScalingInitialized = true;
        }
    }

    /// <summary>
    ///  Creates a new ImageList Control with a default image size of 16x16
    ///  pixels and adds the ImageList to the passed in container.
    /// </summary>
    public ImageList(IContainer container) : this()
    {
        ArgumentNullException.ThrowIfNull(container);

        container.Add(this);
    }

    /// <summary>
    ///  Retrieves the color depth of the imagelist.
    /// </summary>
    [SRCategory(nameof(SR.CatAppearance))]
    [SRDescription(nameof(SR.ImageListColorDepthDescr))]
    public ColorDepth ColorDepth
    {
        get => _colorDepth;
        set
        {
            SourceGenerated.EnumValidator.Validate(value);

            if (_colorDepth == value)
            {
                return;
            }

            _colorDepth = value;
            PerformRecreateHandle();
        }
    }

    private bool ShouldSerializeColorDepth() => Images.Count == 0;

    private void ResetColorDepth() => ColorDepth = ColorDepth.Depth32Bit;

    /// <summary>
    ///  The handle of the ImageList object. This corresponds to a win32
    ///  HIMAGELIST Handle.
    /// </summary>
    [Browsable(false)]
    [EditorBrowsable(EditorBrowsableState.Advanced)]
    [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
    [SRDescription(nameof(SR.ImageListHandleDescr))]
    public IntPtr Handle
    {
        get
        {
            if (_nativeImageList is null)
            {
                CreateHandle();
            }

            return _nativeImageList.HIMAGELIST;
        }
    }

    /// <summary>
    ///  Whether or not the underlying Win32 handle has been created.
    /// </summary>
    [Browsable(false)]
    [EditorBrowsable(EditorBrowsableState.Advanced)]
    [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
    [SRDescription(nameof(SR.ImageListHandleCreatedDescr))]
    [MemberNotNullWhen(true, nameof(_nativeImageList))]
    public bool HandleCreated => _nativeImageList is not null;

    [SRCategory(nameof(SR.CatAppearance))]
    [DefaultValue(null)]
    [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
    [SRDescription(nameof(SR.ImageListImagesDescr))]
    [MergableProperty(false)]
    public ImageCollection Images => _imageCollection ??= new ImageCollection(this);

    /// <summary>
    ///  Returns the size of the images in the ImageList
    /// </summary>
    [SRCategory(nameof(SR.CatBehavior))]
    [Localizable(true)]
    [SRDescription(nameof(SR.ImageListSizeDescr))]
    public Size ImageSize
    {
        get => _imageSize;
        set
        {
            if (value.IsEmpty)
            {
                throw new ArgumentException(string.Format(SR.InvalidArgument, nameof(ImageSize), "Size.Empty"), nameof(value));
            }

            // ImageList appears to consume an exponential amount of memory
            // based on image size x bpp. Restrict this to a reasonable maximum
            // to keep people's systems from crashing.
            if (value.Width <= 0 || value.Width > s_maxImageWidth)
            {
                throw new ArgumentOutOfRangeException(nameof(value), value, string.Format(SR.InvalidBoundArgument, "ImageSize.Width", value.Width, 1, s_maxImageWidth));
            }

            if (value.Height <= 0 || value.Height > s_maxImageHeight)
            {
                throw new ArgumentOutOfRangeException(nameof(value), value, string.Format(SR.InvalidBoundArgument, "ImageSize.Height", value.Height, 1, s_maxImageHeight));
            }

            if (_imageSize.Width != value.Width || _imageSize.Height != value.Height)
            {
                _imageSize = new Size(value.Width, value.Height);
                PerformRecreateHandle();
            }
        }
    }

    private bool ShouldSerializeImageSize() => Images.Count == 0;

    /// <summary>
    ///  Returns an ImageListStreamer, or null if the image list is empty.
    /// </summary>
    [Browsable(false)]
    [EditorBrowsable(EditorBrowsableState.Advanced)]
    [DefaultValue(null)]
    [SRDescription(nameof(SR.ImageListImageStreamDescr))]
    public ImageListStreamer? ImageStream
    {
        get
        {
            if (Images.Empty)
            {
                return null;
            }

            // No need for us to create the handle, because any serious attempts to use the
            // ImageListStreamer will do it for us.
            return new ImageListStreamer(this);
        }
        set
        {
            if (value is null)
            {
                DestroyHandle();
                Images.Clear();
                return;
            }

            if (value.GetNativeImageList() is not { } himl || himl == _nativeImageList)
            {
                return;
            }

            bool recreatingHandle = HandleCreated; // We only need to fire RecreateHandle if there was a previous handle
            DestroyHandle();
            _originals = null;
            _nativeImageList = himl.Duplicate();
            if (PInvoke.ImageList.GetIconSize(new HandleRef<HIMAGELIST>(this, _nativeImageList.HIMAGELIST), out int x, out int y))
            {
                _imageSize = new Size(x, y);
            }

            // need to get the image bpp
            if (PInvoke.ImageList.GetImageInfo(new HandleRef<HIMAGELIST>(this, _nativeImageList.HIMAGELIST), 0, out IMAGEINFO imageInfo))
            {
                PInvokeCore.GetObject(imageInfo.hbmImage, out BITMAP bmp);
                _colorDepth = bmp.bmBitsPixel switch
                {
                    4 => ColorDepth.Depth4Bit,
                    8 => ColorDepth.Depth8Bit,
                    16 => ColorDepth.Depth16Bit,
                    24 => ColorDepth.Depth24Bit,
                    32 => ColorDepth.Depth32Bit,
                    _ => _colorDepth
                };
            }

            Images.ResetKeys();
            if (recreatingHandle)
            {
                OnRecreateHandle(EventArgs.Empty);
            }
        }
    }

#if DEBUG
    internal bool IsDisposed { get; private set; }
#endif

    [SRCategory(nameof(SR.CatData))]
    [Localizable(false)]
    [Bindable(true)]
    [SRDescription(nameof(SR.ControlTagDescr))]
    [DefaultValue(null)]
    [TypeConverter(typeof(StringConverter))]
    public object? Tag { get; set; }

    /// <summary>
    ///  The color to treat as transparent.
    /// </summary>
    [SRCategory(nameof(SR.CatBehavior))]
    [SRDescription(nameof(SR.ImageListTransparentColorDescr))]
    public Color TransparentColor { get; set; } = Color.Transparent;

    private bool UseTransparentColor => TransparentColor.A > 0;

    [Browsable(false)]
    [EditorBrowsable(EditorBrowsableState.Advanced)]
    [SRDescription(nameof(SR.ImageListOnRecreateHandleDescr))]
    public event EventHandler? RecreateHandle
    {
        add => _recreateHandler += value;
        remove => _recreateHandler -= value;
    }

    internal event EventHandler? ChangeHandle
    {
        add => _changeHandler += value;
        remove => _changeHandler -= value;
    }

    private Bitmap CreateBitmap(Original original, out bool ownsBitmap)
    {
        Color transparent = TransparentColor;
        ownsBitmap = false;
        if ((original._options & OriginalOptions.CustomTransparentColor) != 0)
        {
            transparent = original._customTransparentColor;
        }

        Bitmap bitmap;
        if (original._image is Bitmap originalBitmap)
        {
            bitmap = originalBitmap;
        }
        else if (original._image is Icon originalIcon)
        {
            bitmap = originalIcon.ToBitmap();
            ownsBitmap = true;
        }
        else
        {
            bitmap = new Bitmap((Image)original._image);
            ownsBitmap = true;
        }

        if (transparent.A > 0)
        {
            // ImageList_AddMasked doesn't work on high color bitmaps,
            // so we always create the mask ourselves
            Bitmap source = bitmap;
            bitmap = (Bitmap)bitmap.Clone();
            bitmap.MakeTransparent(transparent);
            if (ownsBitmap)
            {
                source.Dispose();
            }

            ownsBitmap = true;
        }

        Size size = bitmap.Size;
        if ((original._options & OriginalOptions.ImageStrip) != 0)
        {
            // strip width must be a positive multiple of image list width
            if (size.Width == 0 || (size.Width % _imageSize.Width) != 0)
            {
                throw new ArgumentException(SR.ImageListStripBadWidth, nameof(original));
            }

            if (size.Height != _imageSize.Height)
            {
                throw new ArgumentException(SR.ImageListImageTooShort, nameof(original));
            }
        }
        else if (!size.Equals(ImageSize))
        {
            Bitmap source = bitmap;
            bitmap = new Bitmap(source, ImageSize);
            if (ownsBitmap)
            {
                source.Dispose();
            }

            ownsBitmap = true;
        }

        return bitmap;
    }

    private int AddIconToHandle(Original original, Icon icon)
    {
        try
        {
            Debug.Assert(HandleCreated, "Calling AddIconToHandle when there is no handle");
            int index = PInvoke.ImageList.ReplaceIcon(this, -1, new HandleRef<HICON>(icon, (HICON)icon.Handle));
            return index == -1 ? throw new InvalidOperationException(SR.ImageListAddFailed) : index;
        }
        finally
        {
            if ((original._options & OriginalOptions.OwnsImage) != 0)
            {
                // This is to handle the case were we clone the icon (see why below)
                icon.Dispose();
            }
        }
    }

    /// <summary>
    ///  Add the given <paramref name="bitmap"/> to the <see cref="ImageList"/> handle.
    /// </summary>
    private int AddToHandle(Bitmap bitmap)
    {
        Debug.Assert(HandleCreated, "Calling AddToHandle when there is no handle");

        // Calls GDI to create Bitmap.
        HBITMAP hMask = (HBITMAP)ControlPaint.CreateHBitmapTransparencyMask(bitmap);

        // Calls GDI+ to create Bitmap
        HBITMAP hBitmap = (HBITMAP)ControlPaint.CreateHBitmapColorMask(bitmap, (IntPtr)hMask);

        int index;
        try
        {
            index = PInvoke.ImageList.Add(this, hBitmap, hMask);
        }
        finally
        {
            PInvokeCore.DeleteObject(hBitmap);
            PInvokeCore.DeleteObject(hMask);
        }

        return index == -1 ? throw new InvalidOperationException(SR.ImageListAddFailed) : index;
    }

    /// <summary>
    ///  Creates the underlying HIMAGELIST handle, and sets up all the
    ///  appropriate values with it. Inheriting classes overriding this method
    ///  should not forget to call base.createHandle();
    /// </summary>
    [MemberNotNull(nameof(_nativeImageList))]
    private void CreateHandle()
    {
        Debug.Assert(_nativeImageList is null, "Handle already created, this may be a source of temporary GDI leaks");

        IMAGELIST_CREATION_FLAGS flags = IMAGELIST_CREATION_FLAGS.ILC_MASK;
        switch (_colorDepth)
        {
            case ColorDepth.Depth4Bit:
                flags |= IMAGELIST_CREATION_FLAGS.ILC_COLOR4;
                break;
            case ColorDepth.Depth8Bit:
                flags |= IMAGELIST_CREATION_FLAGS.ILC_COLOR8;
                break;
            case ColorDepth.Depth16Bit:
                flags |= IMAGELIST_CREATION_FLAGS.ILC_COLOR16;
                break;
            case ColorDepth.Depth24Bit:
                flags |= IMAGELIST_CREATION_FLAGS.ILC_COLOR24;
                break;
            case ColorDepth.Depth32Bit:
                flags |= IMAGELIST_CREATION_FLAGS.ILC_COLOR32;
                break;
            default:
                Debug.Fail("Unknown color depth in ImageList");
                break;
        }

        using (ThemingScope scope = new(Application.UseVisualStyles))
        {
            PInvoke.InitCommonControls();

            _nativeImageList?.Dispose();
            _nativeImageList = new NativeImageList(_imageSize, flags);
        }

        PInvoke.ImageList.SetBkColor(this, (COLORREF)PInvokeCore.CLR_NONE);

        Debug.Assert(_originals is not null, "Handle not yet created, yet original images are gone");
        for (int i = 0; i < _originals.Count; i++)
        {
            Original original = _originals[i];
            if (original._image is Icon originalIcon)
            {
                AddIconToHandle(original, originalIcon);
                // NOTE: if we own the icon (it's been created by us) this WILL dispose the icon to avoid a GDI leak
                // **** original.image is NOT LONGER VALID AFTER THIS POINT ***
            }
            else
            {
                Bitmap bitmapValue = CreateBitmap(original, out bool ownsBitmap);
                AddToHandle(bitmapValue);
                if (ownsBitmap)
                {
                    bitmapValue.Dispose();
                }
            }
        }

        _originals = null;
    }

    // Don't merge this function into Dispose() -- that base.Dispose() will damage the design time experience
    private void DestroyHandle()
    {
        if (HandleCreated)
        {
            _nativeImageList.Dispose();
            _nativeImageList = null;
            _originals = [];
        }
    }

    /// <summary>
    ///  Releases the unmanaged resources used by the <see cref="ImageList" />
    ///  and optionally releases the managed resources.
    /// </summary>
    /// <param name="disposing">
    ///  <see langword="true" /> to release both managed and unmanaged resources;
    ///  <see langword="false" /> to release only unmanaged resources.
    /// </param>
    protected override void Dispose(bool disposing)
    {
        if (disposing)
        {
            if (_originals is not null)
            {
                // we might own some of the stuff that's not been created yet
                foreach (Original original in _originals)
                {
                    if ((original._options & OriginalOptions.OwnsImage) != 0)
                    {
                        ((IDisposable)original._image).Dispose();
                    }
                }
            }

            DestroyHandle();
        }

#if DEBUG
        // At this stage we've released all resources, and the component is essentially disposed
        IsDisposed = true;
#endif

        base.Dispose(disposing);
    }

    /// <summary>
    ///  Draw the image indicated by the given index on the given Graphics
    ///  at the given location.
    /// </summary>
    public void Draw(Graphics g, Point pt, int index) => Draw(g, pt.X, pt.Y, index);

    /// <summary>
    ///  Draw the image indicated by the given index on the given Graphics
    ///  at the given location.
    /// </summary>
    public void Draw(Graphics g, int x, int y, int index) => Draw(g, x, y, _imageSize.Width, _imageSize.Height, index);

    /// <summary>
    ///  Draw the image indicated by the given index using the location, size
    ///  and raster op code specified. The image is stretched or compressed as
    ///  necessary to fit the bounds provided.
    /// </summary>
    public void Draw(Graphics g, int x, int y, int width, int height, int index)
    {
        ArgumentOutOfRangeException.ThrowIfNegative(index);
        ArgumentOutOfRangeException.ThrowIfGreaterThanOrEqual(index, Images.Count);

        HDC dc = (HDC)g.GetHdc();
        try
        {
            PInvoke.ImageList.DrawEx(
                this,
                index,
                new HandleRef<HDC>(g, dc),
                x,
                y,
                width,
                height,
                (COLORREF)PInvokeCore.CLR_NONE,
                (COLORREF)PInvokeCore.CLR_NONE,
                IMAGE_LIST_DRAW_STYLE.ILD_TRANSPARENT);
        }
        finally
        {
            g.ReleaseHdcInternal(dc);
        }
    }

    private static unsafe void CopyBitmapData(BitmapData sourceData, BitmapData targetData)
    {
        Debug.Assert(Image.GetPixelFormatSize(sourceData.PixelFormat) == 32);
        Debug.Assert(Image.GetPixelFormatSize(sourceData.PixelFormat) == Image.GetPixelFormatSize(targetData.PixelFormat));
        Debug.Assert(targetData.Width == sourceData.Width);
        Debug.Assert(targetData.Height == sourceData.Height);
        Debug.Assert(targetData.Stride == targetData.Width * 4);

        // do the actual copy
        int offsetSrc = 0;
        int offsetDest = 0;
        for (int i = 0; i < targetData.Height; i++)
        {
            IntPtr srcPtr = sourceData.Scan0 + offsetSrc;
            IntPtr destPtr = targetData.Scan0 + offsetDest;
            int length = Math.Abs(targetData.Stride);
            Buffer.MemoryCopy(srcPtr.ToPointer(), destPtr.ToPointer(), length, length);
            offsetSrc += sourceData.Stride;
            offsetDest += targetData.Stride;
        }
    }

    private static unsafe bool BitmapHasAlpha(BitmapData bmpData)
    {
        if (bmpData.PixelFormat is not PixelFormat.Format32bppArgb and not PixelFormat.Format32bppRgb)
        {
            return false;
        }

        for (int i = 0; i < bmpData.Height; i++)
        {
            int offsetRow = i * bmpData.Stride;
            for (int j = 3; j < bmpData.Width * 4; j += 4) // *4 is safe since we know PixelFormat is ARGB
            {
                byte* candidate = ((byte*)bmpData.Scan0.ToPointer()) + offsetRow + j;
                if (*candidate != 0)
                {
                    return true;
                }
            }
        }

        return false;
    }

    /// <summary>
    ///  Returns the image specified by the given index. The bitmap returned is a
    ///  copy of the original image.
    /// </summary>
    // NOTE: forces handle creation, so doesn't return things from the original list

    private Bitmap GetBitmap(int index)
    {
        ArgumentOutOfRangeException.ThrowIfNegative(index);
        ArgumentOutOfRangeException.ThrowIfGreaterThanOrEqual(index, Images.Count);

        Bitmap? result = null;

        // if the imagelist is 32bpp, if the image slot at index
        // has valid alpha information (not all zero... which is cause by windows just painting RGB values
        // and not touching the alpha byte for images < 32bpp painted to a 32bpp imagelist)
        // we're not using the mask. That means that
        // we can just get the whole image strip, cut out the piece that we want
        // and return that, that way we don't flatten the alpha by painting the value with the alpha... (ie using the alpha)

        if (ColorDepth == ColorDepth.Depth32Bit)
        {
            if (PInvoke.ImageList.GetImageInfo(this, index, out IMAGEINFO imageInfo))
            {
                Bitmap? tmpBitmap = null;
                BitmapData? bmpData = null;
                BitmapData? targetData = null;
                try
                {
                    tmpBitmap = Image.FromHbitmap((IntPtr)imageInfo.hbmImage);

                    bmpData = tmpBitmap.LockBits(imageInfo.rcImage, ImageLockMode.ReadOnly, tmpBitmap.PixelFormat);

                    int offset = bmpData.Stride * _imageSize.Height * index;
                    // we need do the following if the image has alpha because otherwise the image is fully transparent even though it has data
                    if (BitmapHasAlpha(bmpData))
                    {
                        result = new Bitmap(_imageSize.Width, _imageSize.Height, PixelFormat.Format32bppArgb);
                        targetData = result.LockBits(new Rectangle(0, 0, _imageSize.Width, _imageSize.Height), ImageLockMode.WriteOnly, PixelFormat.Format32bppArgb);
                        CopyBitmapData(bmpData, targetData);
                    }
                }
                finally
                {
                    if (tmpBitmap is not null)
                    {
                        if (bmpData is not null)
                        {
                            tmpBitmap.UnlockBits(bmpData);
                        }

                        tmpBitmap.Dispose();
                    }

                    if (result is not null && targetData is not null)
                    {
                        result.UnlockBits(targetData);
                    }
                }
            }
        }

        if (result is null)
        {
            // Paint with the mask but no alpha.
            result = new Bitmap(_imageSize.Width, _imageSize.Height);

            Graphics graphics = Graphics.FromImage(result);
            try
            {
                HDC dc = (HDC)graphics.GetHdc();
                try
                {
                    PInvoke.ImageList.DrawEx(
                        this,
                        index,
                        new HandleRef<HDC>(graphics, dc),
                        0,
                        0,
                        _imageSize.Width,
                        _imageSize.Height,
                        (COLORREF)PInvokeCore.CLR_NONE,
                        (COLORREF)PInvokeCore.CLR_NONE,
                        IMAGE_LIST_DRAW_STYLE.ILD_TRANSPARENT);
                }
                finally
                {
                    graphics.ReleaseHdcInternal(dc);
                }
            }
            finally
            {
                graphics.Dispose();
            }
        }

        // See Icon for description of fakeTransparencyColor
        if (result.RawFormat.Guid != ImageFormat.Icon.Guid)
        {
            result.MakeTransparent(s_fakeTransparencyColor);
        }

        return result;
    }

    /// <summary>
    ///  Called when the Handle property changes.
    /// </summary>
    private void OnRecreateHandle(EventArgs eventargs) => _recreateHandler?.Invoke(this, eventargs);

    private void OnChangeHandle(EventArgs eventargs) => _changeHandler?.Invoke(this, eventargs);

    // PerformRecreateHandle doesn't quite do what you would suspect.
    // Any existing images in the imagelist will NOT be copied to the
    // new image list -- they really should.

    // The net effect is that if you add images to an imagelist, and
    // then e.g. change the ImageSize any existing images will be lost
    // and you will have to add them back. This is probably a corner case
    // but it should be mentioned.
    //
    // The fix isn't as straightforward as you might think, i.e. we
    // cannot just blindly store off the images and copy them into
    // the newly created imagelist. E.g. say you change the ColorDepth
    // from 8-bit to 32-bit. Just copying the 8-bit images would be wrong.
    // Therefore we are going to leave this as is. Users should make sure
    // to set these properties before actually adding the images.

    // The Designer works around this by shadowing any Property that ends
    // up calling PerformRecreateHandle (ImageSize, ColorDepth, ImageStream).

    // Thus, if you add a new Property to ImageList which ends up calling
    // PerformRecreateHandle, you must shadow the property in ImageListDesigner.
    private void PerformRecreateHandle()
    {
        if (!HandleCreated)
        {
            return;
        }

        if (_originals is null || Images.Empty)
        {
            // spoof it into thinking this is the first CreateHandle
            _originals = [];
        }

        DestroyHandle();
        CreateHandle();
        OnRecreateHandle(EventArgs.Empty);
    }

    private void ResetImageSize() => ImageSize = s_defaultImageSize;

    private void ResetTransparentColor() => TransparentColor = Color.LightGray;

    private bool ShouldSerializeTransparentColor() => !TransparentColor.Equals(Color.LightGray);

    /// <summary>
    ///  Returns a string representation for this control.
    /// </summary>
    public override string ToString()
        => Images is null
           ? base.ToString()
           : $"{base.ToString()} Images.Count: {Images.Count}, ImageSize: {ImageSize}";

    HIMAGELIST IHandle<HIMAGELIST>.Handle => HIMAGELIST;

    internal HIMAGELIST HIMAGELIST => (HIMAGELIST)Handle;
}
